1. Field of the Invention
This invention relates to the field of polarizers and the high throughput mass manufacturing of a new class of polarizars called micropolarizers. Micropolarizers have been developed for use in spatial multiplexing and demultiplexing image elements in a 3-D stereo imaging and display system.
2. Description of Related Art
This invention is related to my co-pending application Ser. No. 07/536,190 entitled xe2x80x9cA System For Producing 3-D Stereo Imagesxe2x80x9d filed on even date herewith incorporated herein by reference in its entirety, which introduces a fundamentally new optical element called a micropolarizer. The function of the micropolarizer is to spatially multiplex and spatially demultiplex image elements in the 3-D stereo imaging and displaying system of the aforementioned co-pending application. As shown in FIG. 1, the micropolarizer (xcexcPol) 1, 2 is a regular array of cells 3 each of which comprises a set of microscopic polarizers with polarization states P1 and P2. The array has a period p which is the cell size and is also the pixel size of the imaging or displaying devices.
It is possible to turn unpolarized light into linearly polarized light by one of three well known means: 1) Nicol prisms; 2) Brewster Angle (condition of total internal reflection in dielectric materials); and 3) Polaroid film. These are called linear polarizers. The Polaroids are special plastic films which are inexpensive and come in very large sheets. They are made of polyvinyl alcohol (PVA) sheets stretched between 3 to 5 times their original length and treated with iodine/potassium iodide mixture to produce the dichroic effect. This effect is responsible for heavily attenuating (absorbing) the electric field components along the stretching direction while transmitting the perpendicular electric field components. Therefore, if P1 is along the stretching direction of the PVA sheets, it is not transmitted, where as only P2 is transmitted, producing polarized light. By simply rotating the PVA sheet 90 degrees, P1 state will now be transmitted and P2 will be absorbed.
The aforementioned three known means for producing polarized light have always been used in situations where the polarizer elements have large areas, in excess of 1 cm2. However, for 3-D imaging with xcexcPols using 35 mm film, to preserve the high resolution, the xcexcPol array period p may be as small as 10 micron. Therefore, there is no prior art anticipating the use of or teaching how to mass produce xcexcPols having such small dimensions.
The present invention provides a means for high through put mass manufacturing of micropolarizer arrays. To use the xcexcPols in consumer 3-D photography, and printing applications, the economics dictate that the cost of xcexcPols be in the range of 1 to 5 cents per square inch. For this reason, the low cost PVA is the basis for the manufacturing process.
The present invention also provides a flexible xcexcPols manufacturing process which can be adapted to low and high resolution situations as well as alternative manufacturing methods, each of which may be advantageous in certain applications and adaptable to processing different polarizer materials. The present invention further provides an electronically controllable xcexcPol.